Blow-piston disconnect apparatus for high voltage

ABSTRACT

A high-voltage blow-piston disconnect apparatus, for use with an electron-negative gas such as sulfurhexafluoride and the like as an arc extinguishing and insulating gas has a blow-piston disconnect switch which in turn has contacts across which an arc develops when the switch opens under load. The disconnect switch includes a blast mechanism for blasting a quenching stream of the gas across the contacts for extinguishing the arc. A filter is connected to the disconnect switch for removing dissociation products produced when the gas extinguishes the arc. A pump is connected with the filter and the disconnect switch for pumping the gas through the filter independent of the quenching stream, whereby the dissociation products are removed from the gas by the filter.

Olsen et al.

1451 June 19, 1973 BLOW-PISTON DISCONNECT APPARATUS FOR HIGH VOLTAGE I [76] Inventors: Willi Olsen, am Leubwald 3, 1 Berlin 13; Heinz Beer, Osianderweg 8, 1 Berlin 27, both of Germany [22] Filed: June 11, 1971 [2]] Appl. No.: 152,069

[30] Foreign Application Priority Data June 50, 1970 Germany P 20 33 853.8

52 US. Cl. ..200/148A 51 Int. Cl. ..H0lh 33/70 58 Field of Search 200/148 A, 148 B,

[56] References Cited UNITED STATES PATENTS 3,250,970 5/1966 Passaquin 200/148 E 5,555,225 1/1971 s6rr 111 6:61.... ZOO/148A 3,566,062 2/1971 Meier et al..... 2007148 B 3,622,725 11/1971 7 McConnell ..20o/14s15 Primary ExaminerRobert S. Macon AttorneyCurt M. Avery, Arthur E. Wilfond, Herbert L. Lerner and Daniel J. Tick [5 7] ABSTRAT A high-voltage blow-piston disconnect apparatus, for use with an electron-negative gas such as sulfurhexafluoride and the like as an arc extinguishing and insulating gas has a blow-piston disconnect switch which in turn has contacts across which an arc develops when the switch opens under load. The disconnect switch includes a blast mechanism for blasting a quenching 6 Claims, 2 Drawing Figures Patented June 19, 1973 3,740,508

2 Sheets-Shut 2 e4 62 65 63 Fig. 2 43% high voltage is known wherein an electron negative gas namely, sulfurhexafluoride (PS is used as the quenching medium for the light are arising when the breaker opens. The quenching medium serves also as an insulating medium since it functions in the space between the high voltage conducting portions and the grounded switch base to insure that a higher dielectric stress is possible as compared to air in this region.

In known blow-piston disconnect switches, the sulfurhexafluoride flows after quenching the light are through a hollow stationary switching member or conspace, thegas can only escape through a filter so that insulating stretches between live high-voltage components and the grounded switch base structure can only come into contact with a purifiedgas and not with the dissociation products which originate from the action of the light are with the gas and which under circumstances can be very aggressive. The filtering of the gas permits a smaller dimensioning of the disconnect switch becausethe insulating stretches or distances can be stressed to a higher degree.

' Accordingly, it is an object of our invention to provide a high-voltage blow piston disconnect apparatus wherein conditions are created which permit a substantial reduction in the size of the blow piston disconnect switch.

. According to a feature of our invention the gas flow through the filter is started with its own pump independent of the blast or stream of the quenching medium. In this manner, the space of the disconnect switch wherein the filter is arranged need no longer be made so large so that the space can accommodate virtually all of the gas of the quenching medium stream without app'reciable pressure buildup. In addition, the construction can be made free of the prerequisites posed by thequenching medium streamin the spacial arrangement of the filter and the guiding of the gas flow serving to filter.

In this connection, it is another object of our invention to provide a high-voltage blow-piston apparatus which will permit the filter to be dimensioned such that ble that it be time-controlled so that the dissociation products and any moisture are removed at definite intervals from the gas used as an insulating medium.

According to another feature of the invention the pump is controlled by the switching movement of the blow-piston disconnect switch, for example, the pump can be started each time that the disconnect switch is switched in or out. in this connection it is important I tact into a space surrounded by metal walls. From this that the time of the pump operation also in this instance does not coincide with the switching movemenflsince the pump is only started by the switching operation. The pump can be turned off after a'definitetime has elapsed or after a definite quantity ofgas has been pumped or a certain number of revolutions have been made or some such similiar criteria.

The pump used in the invention need only be of relatively small power. Therefore, it can be advantageous if a gas flow is developed with a single pump through several blow-piston disconnect switches connect switches connected pneumatically in series. For this purpose, only slightly higher power is needed which,

without additional effort, can be delivered from an energy source standing available for the pumps. in this way, a better efficiency is obtained that if each of the blow-piston disconnect switches connected pneumati cally in series is provided with its own pump.

The invention will now be described with reference to the drawing, wherein:

FIG. 1 illustrates an arrangement of blow-piston disconnect switches in schematic representation and equipped with a filter and individual pump as required by the invention; and

FIG. 2 illustrates, in section, a blow-piston disconnect switch of FIG. 1. I

.The blow-piston disconnect switch arrangement of FIG. 1 includes only the gas linesof the high-voltage breakers which are essential to an understanding of the invention.

R,'S, and T designate three switch housings of a three-pole metal-clad load disconnect switch 1 of H0 KV 3-phase network which functions as a blow-piston circuit breaker. In the switching housings, sulfurhexafluoride gas is contained at a pressure of, for example, 3atmospheres. The gas insulates the live high-voltage components of the switch from the grounded metal capsule which, in the illustrated embodiment, is identical with the switch housing. In addition, when the load disconnect switches open, the gas is placed under a slightly higher pressure with the assistance of a pump arrangement comprising a cylinder and piston, so that a quenching medium flow occurs over the openinglight arc.

The three disconnect-switch housings R, S, T are pneumatically connected in series by connecting conduits 2. The serial connection of the switch housings is connected via a manual blocking'valve 3 at location 4 to the two-pressure gas system of a metal-clad power circuit breaker, the total configuration of which is designated by reference numeral 5.

A manometer 7 is connected to the system at location 4 via a valve 6. A measuring or service connection 8 is also connected via valve6. In addition, at this location the compressor 12 of the two-pressure gas system is connected via a filter l0 and a manual blocking valve 11. As will be explained later in more detail, the compressor l2 feeds the three poles 15, 16 and 17 of the power circuit breaker 5 which comprises a low pressure region 150, 16a, 17a and a high pressure region 15b, 16b, and 17b. Between the high and low pressure regions of each switching pole, there is a blow valve 20 provided. The high and low pressure regions are bridged in common by an over pressure safety valve 42. The pressure difference between the high and low pressure regions of the power circuit breaker amounts approximately to 8 atmospheres. This pressure is used according to the invention to initiate, from time to time, a gas flow through the housings R, S, T of the load disconnect switch 1 independent of the quenching medium flow. This gas fiow serves to purify and dry the sulfurhexafluoride in the load disconnect switch 1 and flows over a manually operated valve 25 and a filter 26 as well as a further valve 27 to the three housings R, S, T pneumatically connected in series. From there, the gas circuit is closed via the valve 3 and the filter as well as the valve 11 and the compressor 12.

.The compressor 12 is bridged by two valves 28 and 29 between which a service connection 30 is provided. An over-pressure valve 31 is connected in parallel thereto. Behind the compressor 12 there is an oil separator 34 which can be blocked by valve 33. From the compressor 12 the gas line connects to a reducing valve 35 and a further valve 36 which can be blocked manually. From valve 36, a connection is made to the high pressure side of the power circuit breaker 5. Between the valves 35, 36, a manometer 39 is connected via a valve 38 as well as a connection 40 for maintenance purposes In addition, at this location, a conduit branches off which connects via a valve 41 to a service connection 30. Reference numeral 45 designates an oil separator which connects, with the compressor 12 and functions to urge oil leaving the compressor back to the compressor.

- In the-illustrated embodiment it is assumed that the compressor 1 of the circuit breaker 5 turns on at definite time intervals by means of time switch 43 at least once daily to urge a definite quantity of gas from the 'low pressure region a, 16a, 17a to the high pressure region 15b, 16b, 17b. According to the invention, this gas quantity is directed through the housing R, S, T of the blow-piston disconnect switch 1, which, with a uniform gaspressure in the housing, exhibits a quenching medium flow for a short time only during the opening instant. Y

The gas fiow initiated with the aid of the power circuit breaker independent of the quenching medium flow directs the gas of the blow-piston disconnect switch over the filter 10 when gas is urged from the low pressure region 'of the power circuit breaker 5 via the compressor into the high pressure region. By means of this daily gas flow which takes place independent of the switching action of the blow-piston disconnect switch, the dissociation products arising from this switching are removed from the gas of the blow-piston disconnect switch 1. In addition, the invention permits. the sulfurhexafluoride to be dried intensely and often, so that the insulating distance in the switch can be held small.

Referring now to FIG. 2, the housing R, S, T of the load disconnect switch 1 includes a metal capsule 49. The metal capsule contains sulfurhexafluoride fo'r insulating the high-voltage conductors 50, 51 which are braced with respect to the metal capsule by disc shaped insulators 52. The movable switching rod 54 of the disconnect switch 1 joins the stationary switchingcontact 55 in theillustrated closed position. The switching contact 55 is carried by high voltage conductor 50 and a good conducting connection with the other conductor 51 is provided via rod 54 and sliding contact part 56, the latter being carried by conductor 51.

As it is seen from the FIG. 2, the switching rod 54 is hollow and is inserted in a blow piston 58 upon which a rod of insulating material 59 is secured. The piston 58 slides in the cylinder 60 which likewise is carried by the high voltage conductor 51. The rod 59 is coupled with a drive crank 61 which is pivotally mounted on a shaft 62. The shaft 62 extends out of the metal capsule 49. On the outside, there is a crank arm 63 which is coupled via a slot 64 with a drive crank 65 of the timing switch 43.

If the disconnect switch 1 is opened, the switching rod 54 moves into open position with a turning of the shaft 62 in a counter-clockwise direction. The piston 58 develops a partial vacuum, so that the sulfurhexafluoride contained in the capsule 49 is drawn out by suction through the inner portion of the switching rod 54 via bores 67. This extinguishes the opening light are.

The timing switch 43 coupled with the shaft 62 is actuated with the switch opening, so thatit reaches the other position indicated by the broken lines. With the swing movement from the first position to the other position, the compressor 12 is started. At the same time, a clock mechanism can be tensioned for example which ensures that the compressor will remain running for definite period of time. Therefore, in each opening movement, the sulfurhexafluoride contained in the capsule 50 is pressued through filters 10, 26 with the aid of the conductor 2.

The invention finds application for different high voltage circuit breakers equipped with blow-piston disconnect switches. The invention is especially advantageous however, in metal-clad high-voltage switching installations in which the electron negative gas exhibits two different pressures during operation. Such installations are at locations at which large switching power is required and are often equipped with a two-pressure gas breaker in which sulfurhexafluoride for quenching the light are flows from a high pressure container with for example l0 atmospheres into a low pressure space 'whereat the gas exhibits a pressure value of 2 atmospheres determined by the insulating capability. The pressure difference between the high pressure container and the low pressure space, which is maintained by means of a compressor, can be advantageously applied for blow-piston disconnect switches according to the invention for developing the gas flow through the filter. In this connection, the pressure difference can drive the gas flow through a blow-piston disconnect switch or through several disconnect switch housings connected in series.

In contrast to the disconnect switch of the German Published Pat. application No. 1,168,996, no storage room is required for the gas flow which permits receivinga quantity of gas required for quenching the light are without any significant pressure buildup. The gas flow desired for the cleansing action can take as long as desired with a disconnect switch according to the invention. It is not dependent upon the switching procedure. In addition, as illustrated in the embodiment, only a relatively small additional effort is required. In the high-voltage metal-clad installation of the invention, with sulfurhexafluoride as the quenching medium and as the insulation medium, there are only required, in addition to the two pressure gas breaker, the filters and connecting conduits between the housings. The connection conduits can be made to pay for themselves in that with their help, the gas pressure in the total metalclad high-voltage breaker installation can be monitored with only a single manometer, as for example, manometer 7.

While the invention has been described by means of a specific example and in a specific embodiment, we do not wish to become limited thereto for obvious modifications will occur to those skilled in the art without departing from the spirit and scope of the invention.

We claim:

1. A high-voltage blow-piston disconnect apparatus for use with an electron-negative gas such as sulfurhexafluoride and the like as an arc extinguishing and insulating gas, said apparatus comprising a blow-piston disconnect switch having contacts acrosswhich an are develops when said disconnect switch opens under load, said disconnect switch including blast means for blasting a quenching stream of thelgas across said contacts for extinguishing said are, a filter connected to said disconnect switch for removing dissociation products produced when'the gas extinguishes said are, pump means connected with said filter and said disconnect switch claim l,.'comp rising time control means connected to said pump means for operating the latter in time dependence. I

3. A blow-piston disconnect apparatus according to claim 1 wherein said disconnect switch comprises actu ating means connected to at least one of said contacts paratus comprising time control means connected to said pump means for operating the latter, said time for moving the same to separate said contacts, said apcontrol means being responsive to said movement for starting the operation of said pump means, said time control means including turn-off means forstopping the operation of said pump means after a predetermined operating time has elapsed.

4. A blow-piston disconnect apparatus according to claim 1 wherein a plurality of said disconnect switches are pneumatically connected in series.

5. A blow piston disconnect apparatus according to claim ll, said apparatus comprising a two-pressure gas breaker, said pump means being a compressor connected to said breaker.

6. A high-voltage metal-clad circuit breaker installa tion for use with an electron-negative gas such as sulfurhexafluoride and the like as an arc extinguishing and insulating gas, said apparatus comprising a blowpiston disconnect switch having contacts across ,which an arc develops when said disconnect switch opens under load, said disconnect switch including blast means for blasting a quenching stream of the gas across said contacts for extinguishing said are, a filter connected to said disconnect switch for removing dissociation products produced when the gas extinguishes said are, a two-pressure gas circuit'breaker pneumatically connected with said filter and said disconnect switch, pump means connected with said filter, said circuit breaker and said disconnect switch for pumping said gas through said filter independent of said quenching stream, whereby the gas flow through said filter in removing said dissociation products is substantially less than the gas flow of said quenching stream. 

2. A blow-piston disconnect apparatus according to claim 1, comprising time control means connected to said pump means for operating the latter in time dependence.
 3. A blow-piston disconnect apparatus according to claim 1 wherein said disconnect switch comprises actuating means connected to at least one of said contacts for moving the same to separate said contacts, said apparatus comprising time control means connected to said pump means for operating the latter, said time control means being responsive to said movement for starting the operation of said pump means, said time control means including turn-off means for stopping the operation of said pump means after a predetermined operating time has elapsed.
 4. A blow-piston disconnect apparatus according to claim 1 wherein a plurality of said disconnect switches are pneumatically connected in series.
 5. A blow piston disconnect apparatus according to claim 1, said apparatus comprising a two-pressure gas breaker, said pump means being a compressor connected to said breaker.
 6. A high-voltage metal-clad circuit breaker installation for use with an electron-negative gas such as sulfurhexafluoride and the like as an arc extinguishing and insulating gas, said apparatus comprising a blow-piston disconnect switch having contacts across which an arc develops when said disconnect switch opens under load, said disconnect switch including blast means for blasting a quenching stream of the gas across said contacts for extinguishing said arc, a filter connected to said disconnect switch for removing dissociation products produced when the gas extinguishes said arc, a two-pressure gas circuit breaker pneumatically connected with said filter and said disconnect switch, pump means connected with said filter, said circuit breaker and said disconnect switch for pumping said gas through said filter independent of said quenching stream, whereby the gas flow through said filter in removing said dissociation products is substantially less than the gas flow of said quenching stream. 